Sprawl is always a big dirty word in the planning and development industry.  By definition (Dictionary.com), Sprawl is “to be stretched or spread out in an unnatural or ungraceful manner“.  This definition is universal and not as focused on planning, but the term as a whole.
I would like to explore why we have sprawl and what is really the root cause.  You may hear this or that about “who” is to blame for sprawl, but it can not be pinned to a group of people.  I believe that it is more engrained in the American culture.  You may often hear that Wal-Mart or Home Depot are to blame for the sprawl of our cities, but why?  These are businesses who know their market and are capitalizing on them.  They can not be blamed for that.  Others blame the “suburbanites” who live in the sprawling portions of our cities.  Again, how do we blame people for desiring to live in a place, that on the surface, seems like a great, safe place with good schools?  I personally understand the desires to live in suburbia, as a parent of two children, you want to provide all of the advantages that you can for your children.  In fact, immediately out of college, I actually lived in the absolute definition of sprawl.
So what causes sprawl and how can we correct it?  This is a very long subject that I’m afraid I am only going to scratch the surface on with this post, but here goes.  My thesis, if you will, is:  Sprawl is a result of democracy, evolution and the dissatisfaction of our built environments. As this continues, more sprawl will occur, primarily as a result of those who inhabited the previous sprawl and are no longer satisfied.
In America, we have many choices and liberties, that make it a fantastic place to live.  This freedom enables us to always look for something “better”, which in the minds of most is newer and with the highest levels of technology.  Who doesn’t want that?  Unfortunately, the vast majority of newer places and buildings are located on the periphery of our cities, because open land is much easier to develop.  Therefore, the original inhabitants of sprawl, create more sprawl through the evolution toward newer, better models of homes, buildings, etc.
I have concluded that one component in the creation of sprawl is the ease in which new development can take place on greenfields.  In the inner city or even the “exurbs”, a developer has a much longer process for developing land.  There are issues with dealing with land constraints, demolition, environmental clean-ups, various neighbors and neighborhood groups, existing infrastructure, etc., etc., etc.  All of these issues make it extremely costly for a developer to do infill development to provide new technologically advanced features to homes.  You cannot blame the developer for doing what is easiest,which is building where land is plentiful, neighbors are few, and there is nothing to demolish or clean-up.
You cannot blame the future occupants of these developments (whether it is an office user, homeowner/renter, industry, retailer, etc.).  They choose the location-based on costs and where their market is.  If the consumer desires new construction or greater technological needs, that’s what is supplied.
So why is sprawl bad?  It spreads our infrastructure longer distances(roads, utilities, etc.) causing the necessary infrastructure to be that much greater (i.e. Interstate highways) and it serves much fewer people.  It creates an auto dependent environment where walking is no longer an optional method of getting from one place to another.  Walking is merely an exercise at this point, which most in the suburbs (due to long commutes, dining out, etc.) do not have the time or patience to do.  Have you noticed that obesity is on the rise?  Don’t think for a second that the correlation is merely a coincidence.  I could go on forever on the problems with sprawl, but not in this post, instead I’ll move on to how we fix this problem.  The following are some ideas that should be utilized collectively, not individually:
A. Incentives: Provide better incentives to infill, redevelopment in our cities.
B. Simplify Approval Process: We could use a simplified zoning process to decrease the amount of time required for approval (i.e. quantative form-based codes with shorter review periods).
C. Subsidies: We could provide other incentives such as subsidized energy, parking, or utilities.
D. Geographical Growth Restraints:  Limiting growth geographically is another solution.  Some cities have implemented this with great success (i.e. Portland, OR and Boulder, CO), some cities and towns are naturally limited by topography or other natural features (i.e. New York City and Deadwood, SD).  This can also have negative results in causing a much higher cost of living in the cities.  There is not a great solution to solving sprawl, but for me it was about education and experience.
I’m afraid I have only scratched the surface on what we can do and the point is that there are options available., The key is in the politics of the city and if your community is resistant to change, it is going to be that much more difficult. 
The light bulb went off for me while reading Suburban Nation (by Andres Duany, Liz Plater-Zyberk and Jeff Speck).  After I finished reading Suburban Nation, I did the calculations (See Quantifying the Effects of Suburban Living) of how much time I wasted in my car and how much money went into the gas and maintenance of that car, the results were mind-boggling.  And as a recovering suburbanite, I can tell you that time is critical and it is the one thing that you cannot have enough of.